1. Field of the Invention
The present invention relates to a spraying apparatus for spraying coating material onto an internal wall of a cylindrical structure. More particularly, the present invention relates to a spraying apparatus for spraying coating material which has a first and a second component.
2. Background Information
Most cities are provided with underground structures for gaining access to public electrical systems and sewers which run under the streets. Such structures which are usually of cylindrical configuration are typically provided with a sealing and support lining. In order to prevent water damage and corrosion from damaging such structures, the wall, ceiling and floor of such structures must periodically be repaired.
Fluid sprayers and coating systems for applying a coating material to the inside of underground access structures and vessels are well known. However, these known systems require the operator thereof to enter into the structure with a coating applicator and to manually spray the walls of the structure with sealant. Not only is the aforementioned process labor intensive but also, the entry into a confined access structure for the application of various chemical coatings presents certain health hazards to the operator.
U.S. Pat. No. 5,405,218 to Hyde Smith discloses the application of an elastomeric material to an underground structure by means of a spray gun used by a workman standing on the bottom of the structure. Additionally, a problem exists in that the workman must maneuver within the structure in order to coat all of the wall surface.
The apparatus according to the present invention overcomes the aforementioned problems by the provision of a robotic spraying assembly that is lowered into an underground structure for spraying an even layer of coating material onto the walls of the structure.
Therefore, it is a primary feature of the present invention to provide a spraying apparatus for spraying coating material that overcomes the problems associated with the prior art arrangements.
Another feature of the present invention is the provision of a spraying apparatus for spraying coating material that applies a coating material of uniform thickness to the structure.
Other features and advantages of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description of a preferred embodiment of the present invention contained herein.
The present invention relates to a spraying apparatus for spraying coating material onto an internal wall of a cylindrical structure having an opening. The apparatus includes a spraying assembly which has a first and a second end. A support is secured to the spraying assembly, the support being selectively movable relative to the opening of the structure for permitting movement of the second end of the spraying assembly axially relative to the structure. A first conduit has a first and a second extremity, the first extremity of the first conduit being connected to a source of a first component of the coating material. The second extremity of the first conduit is connected to the second end of the spraying assembly. A second conduit has a first and a second termination, the first termination of the second conduit being connected to a further source of a second component of the coating material. The second termination of the second conduit is connected to the second end of the spraying assembly. A spray head is connected to the second end of the spraying assembly. The spray head includes a coupling for rotatably coupling the spray head to the second end of the spraying assembly. A nozzle is connected to the coupling, the nozzle being in fluid communication with the second extremity of the first conduit. The nozzle includes a mixing chamber for mixing the components. The arrangement is such that when the spray head is disposed within the structure and is rotated relative to the spraying assembly, the first and second components of the coating material are sprayed onto the internal wall of the structure through the nozzle.
In a more specific embodiment of the present invention, the first end of the spraying assembly defines an anchor for anchoring the spraying assembly to the support. More particularly, the anchor is an eye hook.
Moreover, the support includes a cable having a first and a second termination, the second termination of the cable being secured to the first end of the spraying assembly.
The support further includes a pulley which cooperates with the first termination of the cable and a rail which has a first and a second end. The second end of the rail is secured to the pulley. Also, a vehicle is provided for movably supporting the first end of the rail such that when the rail is extended away from the vehicle, the pulley is positionable above the opening of the structure and when the first end of the rail is retracted towards the vehicle, the pulley and spraying assembly suspended therefrom is retracted into the vehicle.
More specifically, the pulley includes a winch and a control for controlling rotation of the winch such that winding of the cable by the winch is permitted so that controlling of an elevation of the spraying assembly relative to the structure is permitted.
Furthermore, the first conduit is a flexible hose and the second conduit is a further flexible hose.
In a preferred embodiment of the present invention, the first component of the coating material is an epoxy primer and the second component of the coating material is a urethane.
Additionally, the coupling includes a rotary spool.
Also, the second end of the spraying assembly defines an inlet port which is connected to the second extremity of the first conduit. The second end of the spraying assembly also defines a further inlet port which is connected to the second termination of the second conduit. Moreover, the second end of the spraying assembly further defines an enclosure for the rotatable reception therein of the rotary spool such that the rotary spool divides the enclosure into a first annular cavity which is connected to the inlet port and a second annular cavity which is connected to the further inlet port.
The rotary spool defines a first channel which connects the first cavity to the mixing chamber of the nozzle and a second channel which connects the second cavity to the mixing chamber. The channels are disposed such that when the rotary spool is rotated relative to the second end of the spraying assembly, the first component of the coating material flows from the source through the first conduit through the inlet port into the first annular cavity and through the first channel into the mixing chamber of the nozzle. Additionally, the second component of the coating material flows from the further source through the second conduit through the further inlet port into the second annular cavity and through the second channel into the mixing chamber of the nozzle for spray application thereof onto the internal wall of the structure.
Additionally, the spraying apparatus includes a motor for controllably rotating the rotary spool relative to the second end of the spraying assembly.
More particularly, the motor includes a belt drive for rotating the rotary spool.
In an alternative embodiment of the present invention, the motor includes a gear drive for rotating the rotary spool.
The spraying apparatus further includes a plurality of support legs which extend from the spraying assembly for centering the spraying assembly within the cylindrical structure.
More specifically, the plurality of support legs includes a first leg which has an inner and an outer end, the inner end being pivotally secured to the spraying assembly. A first wheel is rotatably secured to the outer end of the first leg for engaging the internal wall for assisting in centering the spraying assembly within the structure. Also, a first support arm has a first and a second extremity, the first extremity of the first support arm being pivotally secured to the second end of the spraying assembly. The second extremity of the first support arm is pivotally secured to the first leg between the inner and outer ends thereof.
Also, a second leg has an inner and an outer end, the inner end being pivotally secured to the spraying assembly. A second wheel is rotatably secured to the outer end of the second leg for engaging the internal wall for assisting in centering the spraying assembly within the structure. A second support arm has a first and a second extremity, the first extremity of the second support arm being pivotally secured to the second end of the spraying assembly. The second extremity of the second support arm is pivotally secured to the second leg between the inner and outer ends thereof;
Moreover, a third leg has an inner and an outer end, the inner end being pivotally secured to the spraying assembly. A third wheel is rotatably secured to the outer end of the third leg for engaging the internal wall for assisting in centering the spraying assembly within the structure. Additionally, a third support arm has a first and a second extremity, the first extremity of the third support arm being pivotally secured to the second end of the spraying assembly. The second extremity of the third support arm is pivotally secured to the third leg between the inner and outer ends thereof.
Also, a biasing device is provided for selectively biasing the wheels towards the internal wall.
Furthermore, the spraying assembly includes a first slide for slidably engaging the inner end of the first leg and a second slide for slidably engaging the inner end of the second leg. A third slide is provided for slidably engaging the inner end of the third leg. The arrangement is such that when the wheels are being biased towards the internal wall, the inner ends of the first second and third legs respectively slide axially along the first, second and third slides respectively.
Many modifications and variations of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description contained hereinafter taken in conjunction with the annexed drawings which show a preferred embodiment of the present invention. However, such modifications and variations fall within the spirit and scope of the present invention as defined by the appended claims.
Included in such modifications would be the application of the spray assembly for coating horizontally disposed pipes and the like. In such an arrangement, the spraying assembly would be movably supported by a horizontally disposed boom or a similar support element.
Additionally, although the concept according to the present invention is particularly applicable to coating cylindrical structures, the apparatus could also be used for coating the internal walls of a structure having a square or rectangular cross sectional configuration.